Means for simulating the natural flow of blood

ABSTRACT

MECHANICAL MEANS FOR SIMULATING THE NATURAL FLOW OF BLOOD, INCLUDING MOTOR MEANS HAVING AN ECCENTRICALLY LOCATED CAM ON ITS DRIVE SHAFT FOR PROVIDING MOTION TO A CRANK LEVER HAVING A MOVABLE PIVOT POINT. A VESSEL CONTAINING A BLOOD SAMPLE UNDER ANALYSIS IS RETAINED ON THE CRANK LEVER TO RECEIVE THE MOTION ESTABLISHED BY THE MECHANICAL MEANS. THE VESSEL CONTAINING THE BLOOD SAMPLE IS ORBITED AROUND A DETECTOR ELEMENT AT A RELATIVELY HIGH SPEED TO ESTABLISH SHEARING EFFECTS AND RESULTING ELECTRO-KINETIC SURFACE EFFECTS BETWEEN THE INNER WALL OF THE VESSEL AND THE SURFACE OF THE DETECTOR ELEMENT CORRESPONDING TO THE SHEARING AND ELECTRO-KINETIC SURFACE FORCES PRESENT IN THE VEINS AND ARTERIES OF AN INDIVIDUAL. THE DETECTOR ELEMENT IS PART OF A CONVENTIONAL BLOOD ANALYSIS DEVICE WHICH MAY PROVIDE EITHER VISUAL OR RECORDED INDICIA REPRESENTATIVE OF THE COAGULATION CHARACTERISTICS OF THE BLOOD SAMPLE.

United States Patent 3,714,815 MEANS FOR SIMULATING THE NATURAL FLOW OF BLOOD Hellmut Hartert, Kaiserslautern, Germany, asslgnor to Fritz Hellige & C0. G.m.b.H., Freiburg im Breisgau,

Germany Filed Apr. 15, 1971, Ser. No. 134,143 Claims priority, application Germany, Apr. 22, 1970, P 20 19 341.3 Int. Cl. G01n 11/10, 33/16 US. Cl. 73-641 4 Claims ABSTRACT OF THE DISCLOSURE Mechanical means for simulating the natural flow of blood, including motor means having an eccentrically located cam on its drive shaft for providing motion to a crank lever having a movable pivot point. A vessel containing a blood sample under analysis is retained on the crank lever to receive the motion established by the mechanical means. The vessel containing the blood sample is orbited around a detector element at a relatively high speed to establish shearing effects and resulting electro-kinetic surface effects between the inner wall of the vessel and the surface of the detector element corresponding to the shearing and electro-kinetic surface forces present in the veins and arteries of an individual. The detector element is part of a conventional blood analysis device which may provide either visual or recorded indicia representative of the coagulation characteristics of the blood sample.

FIELD OF THE INVENTION This invention relates to a device for determining the coagulation characteristics of blood, and more specifically, to means for simulating the natural flow of blood.

DESCRIPTION OF THE PRIOR ART Various devices have been utilized in the past to determine the coagulation characteristics of blood samples. Electrical, optical, chemical and mechanical means have been employed to determine the coagulation characteristics of blood samples. Generally, such determinations are made on a blood sample which is essentially in a stationary or resting position. However, in one type of mechanical device, specifically, Helliges Thromb-Elastograph blood analyzer, the blood sample is slowly oscillated approximately 4 in order that detector means may detect the coagulation characteristics of the blood sample.

The present invention employs such detector means and further provides novel mechanical means for imparting motion to a blood sample that simulates the natural flow of blood in the veins and arteries of an individual. While the aforementioned methods have been somewhat successful in determining the coagulation characteristics of a blood sample, none of these methods have determined the coagulation characteristics of a blood sample that is provided with motion similar to the motion that blood undergoes as it travels through the veins and arteries of an individual.

Accordingly, it is an object of the present invention to provide novel means for simulating, in a blood sample undergoing an analysis, the natural flow of blood as it exists in the veins and arteries of an individual.

It is a further object of the present invention to provide novel means for simulating, in a blood sample undergoing an analysis, the shearing and electro-kinetic surface forces as they exist in the veins and arteries of an individual.

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It is another object of the present invention to provide novel means for establishing orbital motion of a blood sample under analysis in order to precisely determine the exact moment coagulation occurs within the blood sample.

SUMMARY OF THE INVENTION In accordance with the objects set forth above, the present invention provides novel mechanical means for simulating the natural flow of blood. The novel mechanical means may be employed with conventional blood analysis devices which may provide either visual or recorded indicia representative of the coagulation characteristics of blood samples. The novel mechanical means includes motor means having an eccentrically located cam on its drive shaft for providing motion to a crank lever having a movable pivot point. A vessel containing a blood sample under analysis is retained on the crank lever to receive the motion established by the novel mechanical means. The vessel containing the blood sample is orbited around a detector element of the conventional blood analysis device at a relatively high speed to establish shearing effects and resulting electro-kinetic surface effects between the inner wall of the vessel and the surface of the detector element corresponding to the shearing and electro-kinetic surface forces present in the veins and arteries 7 of an individual.

tures of the present invention will become readily apparent from the following detailed description of the preferred embodiment of the invention when taken in conjunction with the accompanying drawing in which:

FIG. 1 is a side elevational view of the novel mechanical means for simulating the natural flow of blood in accordance with the present invention;

FIG. 2 is a perspective view of the novel mechanical means for simulating the natural flow of blood in accordance with the present invention; and

FIGS. 3a, b and 0 compare thromb-elastograms obtained by the prior art method and the method practiced in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2, there are respectively shown a side elevational view and a perspective view of the novel mechanical means 10 for simulating the natural flow of blood. Such novel mechanical means 10 will be discussed relative to its application with a conventional device of the mechanical type used in determining the coagulation characteristics of a blood sample, more spec1fically, Helliges Thromb-Elastograph blood analysis device. It should be understood that the simulated natural flow of blood resulting from the practice of the present invention may be utilized with other devices for determining coagulation characteristics of blood that were discussed earlier.

In Helliges well-known method to produce a thrombelastogram, a blood sample 12 is placed in a vessel 13. A detector element 11, which may be a stainless steel cylindrical cell, is partially submerged in the blood sample 12. The detector element 11 is suspended from a point 14 within a blood analysis device by means of a torsion wire 15, which carries a mirror 16. In the practice of this prior method, the vessel 13 was provided with an oscillatory motion of an amplitude between 3 and 6, preferably at an amplitude of 445. The length of the period for one complete oscillatory motion was between 7 and 12 seconds, preferably 9 seconds. A ray of light was directed toward the mirror 16, which in turn directed the light to either a mirror and visual display arrangement, or to a recording device, such as a camera. Therefore, one was able to either visually observe or record the thrombelastogram. Such a thromb-elastogram, as recorded by the prior method, is illustrated in FIG. 30:. The illustration of FIG. 3a is representative of an envelope of the swing of the mirror 16 in response to the relatively slow oscillatory motion imparted to the blood sample 12.

On the other hand, it has been found by experimentation that by providing the blood sample 12 with a motion that simulates the natural fiow of blood in the veins and arteries of an individual, as practiced in accordance with the principles of this invention, one may produce a thromb-elastogram as illustrated in FIG. 3b. As can be readily appreciated by comparing the thromb-elastogram of 3a with the thromb-elastogram of 3b, the envelope of 3b clearly defines the moment of coagulation of the blood sample 13.

Referring now specifically to the mechanical means for simulating the natural flow of blood, there is shown a crank lever 17 which is supported by a first support member 18, which in turn is rigidly mounted by a second support member 19. The second support member 19 is rigidly mounted within an opening 20 of a housing 21 which is illustrated in FIG. 2 and is schematically represented in FIG. 1. The vessel 13 containing the blood sample 12 may be placed in an opening 27 of the crank lever 17 and is retained in place by means of the retaining ridge 13a of the vessel 13. The opening 27 is slightly larger than the outside diameter of the vessel 13 so that the vessel 13 will respond to any motion of the crank lever 17. The crank lever 17 includes a movable pivot point 17a and an exaggerated U-shaped cam follower 17 There is further shown a guide support member 25 which may be rigidly mounted to the first support member 18 by means of screws, as shown. A tension spring 26 connected between the guide support member 25 and the crank lever 17 ensures that the pivot point 117a may slide back and forth along the surface of the guide sup port member 25 and further ensures that the cam follower 17b remains in contact with an eccentric cam 24.

A motor 22 provides motion to the crank lever 17 by means of a shaft 23 having an olfset portion in the form of the eccentric cam 24. The motor 22 operates at approximately 3000 r.p.m. to drive the eccentric cam 24. The diameter of the illustrated circles produced by the rotation of the eccentric cam 24 is relatively small, in the order of approximately .05 mm. Thus, the circumferential speed of a point on the illustrated circles is in the order of approximately 75 mm. per second.

Therefore, due to the movement of the crank lever 17, as illustrated, the blood sample 12 orbits around the detector element 11 at a relatively high frequency. This orbiting motion establishes shearing effects and resulting electro-kinetic surface effects between the inner wall of the vessel 13 and the surface of the detector element 11 corresponding to the shearing and electro-kinetic surface forces present in the veins and arteries of an individual. It has been found that by simply increasing the frequency of the oscillatory motion of the prior art method the above-mentioned desired effect is not established. Evidently, in such simple oscillatory motion, the surfaceactive forces are extinguished at each reversing of the oscillatory motion.

Referring now to FIGS. 3a, b and 0, there are shown schematic representations of three thromb-elastograms. The respective straight lines on the left side of all three thromb-elastograms represent the time prior to the formulation of any blood clots in the blood samples under analysis. When blood clots are developing within the respective blood samples under analysis, the detecting ele ment 11 will respond to the forces established, thus, the mirror 16 will oscillate as described earlier. The oscillations of the mirror 16 will provide the respective envelope curves of the illustrated thromb-elastograms. FIG. 3a

represents a thromb-elastogram obtained using the previ ously discussed prior art method of simply oscillating the blood sample slowly back and forth approximately 4. The forming of the blood clot of the thromb-elastogram of FIG. 3a is slowly detected and one cannot determine the exact moment that the blood clot is developed. Thus, one cannot precisely determine the length of time before the blood clot develops.

FIG. 3b represents a thromb-elastogram obtained by using the method practiced by the present invention. As is clearly evident from a comparison of FIGS. 3a and 3b, the blood sample under the influence of the orbiting motion provided by the present invention produces a thromb-elastogram illustrating the exact moment that the blood clot is developed. Thus, one can precisely determine the length of time before the blood clot develops. The detection of the sudden increase in the ruggedness of the blood clot is the consequence of the polymerization process of forming the fibrine fibers that are traveling extraordinarily fast under the influence of the orbiting motion practiced in the present invention.

The thromb-elastograms of FIGS. 3a and 3b have bowed portions in the envelope of their respective curves. These bowed portions in the thromb-elastograms result from the presence of thrombocytes in the blood samples under analysis. FIG. 30 represents a thromb-elastogram of a blood sample undergoing an analysis according to the method practiced by the present invention; however, the blood sample under analysis is free of thrombocytes. Therefore, the curve of the envelope is not bowed. As is clearly shown, the forming of the blood clot of FIG. 3c is detected at the same time as the forming of the blood clot of FIG. 3b. Thus, it is clearly evident that the resulting formation of the blood clots of FIGS. 3b and 30 results from the orbiting motion provided by the present invention and is independent of the presence of thrombocytes in the blood sample.

Thus, although the present invention has been shown and described with reference to particular embodiments, for example, an exaggerated U-shaped cam follower 17b to provide circular orbiting of the blood sample 12, nevertheless, various changes and modifications obvious to a person skilled in the art to which the invention pertains, for example, the use of an elliptical-shaped cam follower to provide elliptical orbiting of a blood sample, are deemed to lie within the spirit, scope and contemplation of the invention, as set forth in the appended claims.

What is claimed is:

1. Apparatus for providing indicia representative of the coagulation characteristics of a blood sample comprising:

a vessel for retaining a blood sample;

detecting means at least partially submerged within said blood sample; and

means cooperating with said vessel for providing movement to said vessel for simulating the natural flow of blood of said blood sample, said means comprising drive means having an eccentrically located cam, and mechanical means having a cam follower cooperating with said eccentrically located cam or said drive means, said mechanical means being connected to said vessel for orbiting said vessel around said detecting means in response to saiddrive means.

2. Apparatus as recited in claim 1 wherein said mechanical means comprises:

a support member;

biasing means having a first end and a second end;

a crank lever having an opening on one end to retaln said vessel, said cam follower being located on the opposite end, said crank lever being connected to said first end of said biasing means, and said crank lever having a movable pivot point located approximately midway between said opposite ends of said crank lever; and

guide means rigidly mounted to said support member,

said guide means being in contact with said movable pivot point of said crank lever, said guide means References Cited being connected to said second end of said biasing UNITED STATES PATENTS means for ensuring that said crank lever provides orbital motion to said vessel. 3053078 9/1962 i 7359 X 3. Apparatus as recited in claim 2 wherein said drive 5 2814945 12/1957 Mlchaux et 73 59 means is a motor operating at approximately 3000' revOlu- 3503709 3/1970 YQChem 73 64'1 X tions per minute, and the orbital motion of the opposite 3518'057 6/1970 'Glordano 23-230 B X ends of said crank lever defines respective circles having a FOREIGN PATENTS diameter of approximately .05 millimeter. 872 277 2/1953 Germany 73 59 4. Apparatus as recited in claim 1 wherein said move- 10 1,148:113 4/1969 Great d 73 59 ment provided said vessel establishes shearing effects and resulting electro-kinetic surface effects between the inner S. CLEMENT SWISHER, Primary Examiner surface of said vessel and the surface of said submerged J W ROSKOS Assistant Examiner part of said detecting means corresponding to the shearing and electro-kinetic surface forces present in the veins and 15 us CL X arteries of an individual. 23-230 B; 73-59 

